When drill pipe, tubing, etc. becomes stuck in longitudinal or radial movement due to cave-ins in the bore hole, it is frequently necessary to remove the free section of the pipe or tubing which is above the point of sticking. To achieve this, it is known in the art to use explosives that are detonated at the first free joint above the stuck point. The use of explosives in this operation is disadvantageous from three aspects:
(1) If a shot fails to result in loosening the joint, then the whole procedure must be repeated, i.e. remove the torque, remove the shot tool, reload, replace shot tool, retorque and fire.
(2) The dynamic pressure pulses of explosives are such that the drill pipe and/or pipe joint could be easily damaged thereby.
(3) Debris resulting from explosive charges can block fluid circulation through the pipe further complicating the recovery procedure.